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of its wider application as polyelectrolyte, surfactant and
also in ion exchange resins. The polymerization behavior of
these IPCs was investigated in detail by free radical poly-
merization (FRP), atom transfer radical polymerization
(ATRP), and reversible addition-fragmentation chain transfer
(RAFT) mediated polymerizations. Controlled radical poly-
merization techniques were used here as the polymerization
techniques like ATRP,19,20 single-electron transfer living radi-
cal polymerization (SET-LRP),21 and RAFT20,22 can be
expected to provide greater control over the structure of the
polymers synthesized and also for the purpose of verifying
the suitability of these techniques for surface initiated poly-
merizations23 of asymmetric IPCs. Aqueous dispersion poly-
merization using free radical initiators was also used to
produce copolymers. Finally, the highly ionic interactions of
these IPC-based copolymers have been exploited to synthe-
size ionically crosslinked PMMA. Such copolymers of PMMA
even with 5–6 mol % IPC content yielded insoluble poly-
mers. The swelling studies of these copolymers which are
crosslinked by ionic interactions are also described herein.
60 C for 48 h. The mixture was cooled down to room tem-
perature, and the bottom layer was separated out and
washed with THF further (2 3 25 mL). The brownish liquid
product 3-hexyl-1-vinylimidazolium bromide (C6VImBr) was
then dried in a vacuum oven. Yield 14.22 g (51.63%). 1H
NMR (400 MHz, d4-MeOD, d): 0.92 (t, 3H, ACH3), 1.34–1.41
(m, 6H, 33CH2), 1.94 (t, 2H, CH2), 4.28 (t, 2H, NACH2), 5.45
(d, 1H, vinyl CH2), 5.96 (d, 1H, vinyl CH2), 7.28 (t, 1H, vinyl
CH), 7.79 (s, 1H, imidazole NACH), 8.02 (s, 1H, imidazole
CHAN1), 9.3 (s, reduced intensity, imidazole NACHAN1).
13C NMR (400 MHz, d4-MeOD, d): 14.29, 23.49, 26.96, 30.92,
32.28, 51.28, 109.96, 120.79, 124.45, 129.83.
Step II: Aqueous solution (50 mL) of 3-hexyl-1-vinylimidazo-
lium bromide (C6VImBr, 14.22 g, 54.9 mmol) was added to
an aqueous solution (100 mL) of sodium 4-styrenesulfonate
(SSS, 13.575 g, 65.04 mmol) and the homogeneous mixture
was stirred at room temperature overnight. The ion pair
monomer product was extracted from this homogeneous so-
lution using CHCl3 (3 3 75 mL). The chloroform phase was
then dried over anhydrous MgSO4 and removed in a rotary
evaporator followed by drying in a vacuum oven at room
temperature finally to yield white powder which was stored
in a freezer before use. Yield 19.5 g, 98%. The product was
soluble in MeOH, CHCl3, acetone, THF, DMF, CAN and insolu-
ble in toluene and water. 1H NMR (400 MHz, d4-MeOD, d):
0.92 (t, 3H, ACH3), 1.33–1.36 (m, 6H, 33CH2), 1.89 (t, 2H,
CH2), 4.22 (t, 2H, NACH2), 5.32 (d, 1H, styrene vinyl CH2),
5.42 (d, 1H, imidazole vinyl CH2), 5.83–5.92 (m, 2H, vinyl
CH2 of imidazole and styrene), 6.73–6.80 (m, 1H, styrene
vinyl CH), 7.19–7.25 (m, 1H, imidazole vinyl CH), 7.48 (d,
2H, styrene aromatic CH), 7.73 (d, 1H, imidazole NACH),
7.78 (d, 2H, styrene aromatic CH), 7.97 (d, 1H, imidazole
CHAN1), 9.29 (s, reduced intensity, imidazole NACHAN1).
13C NMR (400 MHz, d4-MeOD, d): 14.30, 23.48, 26.95, 30.89,
32.27, 51.23, 109.86, 115.90, 120.71, 124.40, 127.07, 127.28,
129.81, 137.27, 140.88, 145.67. Anal. calcd. For
EXPERIMENTAL
Materials and Characterizations
All chemicals including RAFT agents were purchased from
Sigma-Aldrich and Alfa Aesar. 2,20-Azobisisobutyronitrile
(AIBN) was obtained from HalloChem Pharm Co. AIBN was
purified by recrystallization from absolute alcohol. Spectra/
Por regenerated cellulose membrane tubing for dialysis
(MWCO 1000 and 3500) was bought from Spectrum Labs.
NMR spectra were recorded on a 400 MHz Bruker Ultra-
Shield AVANCE 400SB spectrometer. Elemental microanalysis
was performed using Eurovector E300 elemental analyzer.
Thermogravimetric analysis (TGA) was performed under N2
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atmosphere at a heating rate of 10 C/min using SDT-2960T
TA instruments. The differential scanning calorimetry (DSC)
was performed using Perkin Elmer Pyris Diamond Hyper DSC
instruments at a heating rate of 10 ꢀC/min under N2. The
aqueous GPC system was equipped with a Delta 600 HPLC
pump, a 600 controller, a 717 plus autosampler, a 2487 dual
absorbance detector, and a 2414 refractive-index detector, all
from Waters. The following GPC columns were arranged in se-
ries: Ultrahydragel guard, and Ultrahydragel 120 (7.8 mm ID
3 300 mm) and an Ultrahydragel Linear (7.8 mm ID 3 300
mm). The eluant (0.1 M NaNO3 in deionized water) flow rate
was 0.7 mL/min and the columns were maintained at 30 ꢀC.
The results were obtained using polyethylene oxide (PEO) and
polyethylene glycol (PEG) calibrations.
C
19H26N2O3S: C 62.96, H 7.33, N 7.73, S 8.85, O 13.24%;
Found: C 62.26, H 7.10, N 7.62, S 8.41, O 12.91%.
Synthesis of IPC2
This novel comonomer was synthesized by a modified
method of Qiu et al.24 in a two-step procedure as given
below and stored in freezer before use.
Step I: Excess 1-bromohexadecane (38.93 g, 127.5 mmol)
was added to a solution of 1-vinylimidazole (VIm, 8 g, 85
mmol) in dry THF (80 mL) in a round bottom flask fitted
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with condenser and the solution was heated at 60 C for 48
h. The homogeneous solution was then concentrated to ꢁ50
mL and the product was precipitated from excess ether (120
mL). The white product 3-hexadecyl-1-vinylimidazolium bro-
mide (C16VImBr) was then dried in a vacuum oven at room
temperature to produce white powder. Yield 15.25 g, 45%.
1H NMR (400 MHz, d4-MeOD, d): 0.91 (t, 3H, ACH3), 1.30-
1.39 (m, 26H, 133CH2), 1.94 (t, 2H, CH2), 4.28 (t, 2H,
NACH2), 5.47 (d, 1H, vinyl CH2), 5.96 (d, 1H, vinyl CH2),
7.28 (t, 1H, vinyl CH), 7.79 (s, 1H, imidazole NACHAN1),
Synthesis of Vinylimidazole (VIm) Based IPCs
Synthesis of IPC1
This novel comonomer was synthesized in a two-step proce-
dure as given below and stored in freezer before use.
Step I: Excess 1-bromohexane (21.048 g, 127.5 mmol) was
added to a solution of 1-vinylimidazole (VIm, 10 g, 106.25
mmol) in dry tetrahydrofuran (100 mL) in a round bottom
flask fitted with condenser and the mixture was heated at
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JOURNAL OF POLYMER SCIENCE, PART A: POLYMER CHEMISTRY 2013, 51, 3260–3273
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